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Arctic ozone depletion may be causing toxic algae to grow

The microscopic plants that support all life in the oceans are dying off at a dramatic rate, according to a study that has documented for the first time a disturbing and unprecedented change at the base of the marine food web.

Scientists have discovered that the phytoplankton of the oceans has declined by about 40 per cent over the past century, with much of the loss occurring since the 1950s. They believe the change is linked with rising sea temperatures and global warming.

If the findings are confirmed by further studies it will represent the single biggest change to the global biosphere in modern times, even bigger than the destruction of the tropical rainforests and coral reefs, the scientists said yesterday.

Phytoplankton are microscopic marine organisms capable of photosynthesis, just like terrestrial plants. They float in the upper layers of the oceans, provide much of the oxygen we breathe and account for about half of the total organic matter on Earth. A 40 per cent decline would represent a massive change to the global biosphere.

“If this holds up, something really serious is underway and has been underway for decades. I’ve been trying to think of a biological change that’s bigger than this and I can’t think of one,” said marine biologist Boris Worm of Canada’s Dalhousie University in Halifax, Nova Scotia. He said: “If real, it means that the marine ecosystem today looks very different to what it was a few decades ago and a lot of this change is happening way out in the open, blue ocean where we cannot see it. I’m concerned about this finding.”